1. Field of the Invention
This invention relates to an apparatus and process for improved detectable warning tiles and installation of tiles in a bonding substrate, such as an adhesive, concrete or asphalt. The invention is especially useful in platform applications, such as those found in light rail platforms.
2. Description of the Related Art
A tile is a manufactured piece of hard-wearing material such as ceramic, cement, stone, metal, plastic, or glass. Flooring tiles in particular are commonly made of ceramic, clay, or stone. Traditionally, floor tiles have typically been set into mortar or “grout,” which consists at least of water, sand, and cement (with polymers, color tint, and other additives being common).
More specialized flooring tiles exist in which a protuberance (such as a truncated dome or stud) extends from the top surface of the tile and provides a “detectable warning” of a potentially dangerous situation, such as the end of a curb or the entry to an escalator. In the United States, under the Americans with Disabilities Act (ADA) of 1990, such “detectable warning tiles” are defined as “standardized surface features built in or applied to a walking surface or other elements to warn of hazards on a circulation path.”
Essentially two types of methods are used to install detectable warning tiles: setting tiles in freshly poured (“wet”) cementitious or asphalt material or attaching warning tiles to the top of a surface with screws or other fasteners and sometimes adhesives.
While attaching warning tiles to a surface generally is faster and less expensive in the short term, it suffers from the inherent problem of leaving a raised surface that may become a tripping hazard. Moreover, warning tiles that are not embedding in concrete or similar material often are less durable, in that cracking, chipping, and detachment of the tile can more readily occur. This increases the time and resources that must be spent to maintain, repair, or replace surface-applied warning tiles.
While typically more costly and time consuming, setting warning tiles in wet concrete, asphalt, or a similar substrate and then allowing the substrate to harden or cure provides a level finished-surface and a tile that is strongly bonded to its substrate material. Thus, this method is often the method of choice in new construction and some retrofitting applications. However, setting a warning tile in concrete does not always guarantee improved durability. Indeed, if the installation is made improperly, the tile may crack or become loose. This is especially the case in today's market in which light rail and other platforms requiring detectable warning tiles are being build in increasing numbers.
Such platforms have exposed edges. Since detectable warning tiles must be installed at the platform edge, it often is the case that the tiles are damaged from impacts and other wear occurring at the edge. Thus, there continues to be a need for improved detectable warning tiles and methods for installing tiles that are offer improved durability and that are especially well suited platform-edge applications.